printk

The printk function and dmesg methods are common means for kernel debugging .

printk函数和dmesg方法都是用来进行内核调试的常用方法。

The printk call can be called from any context in the kernel .

printk可以在内核的任意上下文中调用。

One of the first differences you 'll see in the use of printk is more about protocol and less about function .

在使用printk时，您首先会发现的不同点更多是关于协议，而不是功能的。

Note the use of printk here : this is the kernel printf function .

注意此处printk的用法：这是内核的printf函数。

A printk user who desires rate limiting calls the printk_ratelimit function .

如果一个printk用户要求进行速度限制，那么该用户就需要调用printkratelimit函数。

The printk function relies on a feature of the C language called string literal concatenation .

printk是基于C语言中一个名为字符串逐字连接的特性。

H ; its implementation is in . / linux / kernel / printk . c.

而它的实现位于./linux/kernel/printk.c。

Note that within the kernel , rate limiting is caller controlled and is not implemented within printk .

注意，在内核中，速度限制是由调用者控制的，而不是在printk中实现的。

Printk 's can be inserted without rebuilding and rebooting the kernel .

不需要重新编译和重新引导内核就可以插入printk。

You are now ready to insert printk 's and collect debugging information dynamically and unobtrusively by writing simple Kprobes modules .

您现在就已经准备就绪，可以插入printk并通过编写简单的Kprobes模块来动态而且无干扰地收集调试信息。

Logging within the kernel is performed using the printk function , which shares similarity with its user space counterpart , printf ( print formatted ) .

内核的日志是通过printk函数实现的，它与用户空间对应函数printf（按格式打印）具有相似的作用。

The printk_delay value represents the number of milliseconds to delay between printk messages ( to add readability in some scenarios ) .

printkdelay值表示的是printk消息之间的延迟毫秒数（用于提高某些场景的可读性）。

You can insert printk 's at the beginning of a routine or at any offset in the function ( the offset must be at the instruction boundary ) .

您可以在例程的开头或者函数中的任意偏移位置插入printk（偏移量必须在指令范围之内）。

The string passed into printk is then copied into the kernel log buffer using a special function that manages the bounds of the ring ( emit_log_char ) .

这个字符串会被传递给printk，然后它会被一个管理缓冲边界（emitlogchar）的特殊函数复制到内核日志缓冲区中。

The syslog call ( called do_syslog within the kernel in . / linux / kernel / printk . c ) is a relatively small function that provides the ability to read and control the kernel ring buffer .

syslog调用（在内核中调用./linux/kernel/printk.c的dosyslog）是一个相对较小的函数，它能够读取和控制内核环缓冲区。

Note that if a caller does not provide a log level within printk , a default of KERN_WARNING is automatically used ( meaning that only log messages of KERN_WARNING and higher priority will be logged ) .

注意，如果调用者未将日志级别提供给printk，那么系统就会使用默认值KERNWARNING（表示只有KERNWARNING级别以上的日志消息会被记录。）

The call begins in . / linux / kernel / printk . c in the printk function , which calls vprintk ( in the same source file ) after resolving the variable-length arguments using va_start .

这个调用从./linux/kernel/printk.c中的printk函数开始，它会在使用vastart解析可变长度参数之后调用vprintk（在同一个源文件）。